Conventional displays are designed on basis of spatially “simultaneous additive color mixing process.” FSC displays, on the other hand, in which color displaying can be carried out with one pixel, use a “successive additive color mixing process” by a temporally-divided backlight system. FSCDs offer several fundamental advantages over conventional transmissive and emissive displays. The absence of sub-pixels and color filters give high transmission, large aperture ratio, and the possibility of at least three times higher pixel density as well as three times less power consumption. Furthermore, the primary chromaticity is determined solely by the light sources, which enables wider gamut. However, an inherent problem of FSCDs is the presence of saccadic color break-up artifacts. These artifacts may be eliminated only by increasing the frame rate, which requires LCs with fast response time.
Due to fundamental working principle of FSCDs, conventional nematic LCs cannot satisfy the high frequency requirement to avoid color break up. However, a number of other LC-based architectures and electro-optical modes have been proposed for FSCDs to attempt to improve the response time for LCs.
One approach uses the flexoelectric effect of short pitch cholesteric LCs shows a response time of ˜200 μs. This technology, however, has several material issues and a very complicated fabrication procedure.
In some alternate approaches, polymer-stabilized blue phase liquid crystal and cholesteric liquid crystal have been proposed with very fast response time (around 1 ms). Drawbacks which limit these technologies are the very high requirement of driving voltage at the electric field of E=20 V/μm and several material issues.
FLCs, because of their fast response times, are another possibility for FSCDs. One approach is a polymer stabilized FLC to enable monostable V-shape switching (hereinafter abbreviated PSV-FLCD). Another approach is a photoaligned fast FLC display using deformed helix ferroelectric (hereinafter abbreviated DHF) mode LC used for FSCDs, for example, as described in U.S. patent application Ser. No. 13/110,680 (published as U.S. Publication No. 2011/0285928), which is incorporated herein by reference in its entirety. The electronic driving scheme for this DHF FLC includes amplitude modulation, which may increase the fabrication expense.
Recently, in-plane switching (IPS), Advanced Super Dimension Switching (ADS), and fringe field switching (FFS) have been used in high-end LCD applications because they provide wide view angle and high resolution. However, such conventional IPS, ADS and FFS devices suffer from severe drawbacks in terms of image-sticking due to residual DC (RDC) of the alignment layer, as well as non-uniformity and loss of light transmittance at the edge of the pixels due to non-uniformity liquid crystal alignment. Image flickering is also an issue with respect to FFS displays, and complex fabrication and manufacturing costs are additional drawbacks as well.
While FLCs, due to their in-plane switching behavior, provide the advantages of fast switching speed and lower power consumption along with simpler and cheaper fabrication. However, due to certain limitations of FLCs (e.g., the geometrical, optical and mechanical defects associated therewith), FLCs have not conventionally been adopted for high-end LCD applications.